Cabinet including optical bulkhead plate for blown fiber system

ABSTRACT

A cabinet is provided for managing the connections between a feeder cable and a distribution cable wherein the distribution cable is a blown optical fiber. The cabinet includes shelves for holding splices between the feeder cable and the distribution cable. The shelves also include microduct holders for holding each of the microducts associated with the distribution cable.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No. 11/970,439 filed on Jan. 7, 2008, which is a divisional of U.S. patent application Ser. No. 11/249,726 (now U.S. Pat. No. 7,330,626) filed on Oct. 13, 2005, which claims the benefit of U.S. Provisional Application Ser. No. 60/713,622, filed Aug. 31, 2005. The disclosures of all of the above identified applications are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to fiber distribution cabinets for holding fiber optic telecommunications terminations and equipment.

BACKGROUND OF THE INVENTION

Fiber distribution cabinets are known for holding and managing fiber optic cables, splices, and terminations for cables extending to and from the cabinets. In some cases, the cables extending to and from the cabinets are underground cables. In some systems, conduit is laid between a remote site and a cabinet and then optical fiber is blown through the conduit when needed at a later time.

There is a need for cabinets which hold and manage the fiber optic cables, splices, and terminations, as well as interfacing with the conduit through which blown fibers are provided.

SUMMARY OF THE INVENTION

The present invention relates to cabinets and methods including an enclosure which has a first cable entry and a second cable entry. The cabinet includes structure within the interior for connecting the first cable to the second cable. In one preferred embodiment, a plurality of shelves or trays is provided for holding the connections, such as the splices between the first and second cables. The trays also include holders for holding the conduit including microducts which are used to receive blown fiber as part of the first or second cables.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a fiber optic distribution cabinet, shown with both front and rear doors open;

FIG. 2 is a partial exploded front perspective view of the distribution cabinet of FIG. 1;

FIG. 3 is a front elevational view of the distribution cabinet of FIG. 1;

FIG. 4 is a rear perspective view of the distribution cabinet of FIG. 1 with portions removed;

FIG. 5 is a rear elevational view of the cabinet of FIG. 1, showing feeder subunit cables routed to a splice drawer;

FIG. 6 is a top perspective of the splice drawer showing feeder pigtails connected to splice trays in the splice drawer;

FIG. 7 is a top view of the splice drawer of FIG. 6, showing the feeder subunit cables joined to the feeder pigtails at the splice trays;

FIG. 8 is a top view of one of the splice trays of the splice drawer of FIG. 6, showing one fiber splice;

FIG. 9 is a top perspective view of a connector drawer of the cabinet of FIG. 1, showing the feeder pigtails joined to splitter input cables at a termination arrangement;

FIG. 10 is a top view of the connector drawer of FIG. 9;

FIG. 11 is a front elevational view of the cabinet of FIG. 1, showing splitter input cables routed from the connector drawer to one of the splitter modules;

FIG. 12A is a front elevational view of a splitter chassis including two splitter modules;

FIG. 12B is a front elevational view of the cabinet of FIG. 1, including the chassis of FIG. 12A with one splitter module;

FIG. 13 is a front elevational view of the cabinet of FIG. 1, showing splitter output cables routed to a connector storage panel;

FIG. 14 is a front elevational view of the cabinet of FIG. 1, showing splitter output cables routed to two connector panels;

FIG. 15 is an enlarged view of a portion of one of the connector panels showing a connection between a splitter output cable and a distribution pigtail;

FIG. 16 is a top view of one of the connector panels;

FIG. 17 is an enlarged perspective view of a lower portion of the cabinet of FIG. 1, showing clamping of a conduit to the cabinet, and including microducts extending from the conduit;

FIG. 18 is a front elevational view of the cabinet of FIG. 1, showing various conduits and microducts extending to microduct holders;

FIG. 19 is a top view of one of the shelves of the cabinet of FIG. 1, showing connections between distribution pigtails and fibers extending from the microducts at splice trays;

FIG. 20 is a top view of one of the splice trays of the shelf of FIG. 19, showing one fiber splice;

FIG. 21 is a front perspective view of one of the shelves;

FIG. 22 is a rear perspective view of the shelf shown in FIG. 21;

FIG. 23 is a schematic view showing the various elements of the cabinet of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1-4 and 23, one preferred embodiment of a telecommunications fiber distribution cabinet 10 is shown. Cabinet 10 includes an enclosure 12 for housing connections between a first cable 14 and a second cable 16. In one embodiment, first cable 14 is a feeder cable, and second cable 16 is a distribution cable. As will be described below, enclosure 12 houses the connections between individual optical fibers associated with each of first and second cables 14, 16. Cabinet 10 is also useful in interfacing with hollow conduit, such as ducts, which can be used for later insertion of optical fibers, such as with a blowing operation.

Cabinet 10 includes a base 17, first and second sides 18, 20, an open front 22, and an open rear 24. First and second pivotally mounted doors 26, 28 are mounted adjacent to open front 22 and open rear 24, respectively. Enclosure 12 defines an enclosed interior 30 which receives first and second cables 14, 16 and holds and manages the connections between the cables.

Referring also now to FIGS. 5-22 in addition to FIGS. 1-4 and 23, cabinet 10 includes a first cable entry 32 through base 17. First cable 14 can be clamped with a clamp 34. Typically first cable 14 is an underground cable entering cabinet 10 from beneath base 17. Clamp 34 can be mounted to an inner vertical panel 36 which further includes cable ties 37 and a cable manager 38. Such devices are useful for guiding first cable 14 to the various interconnection structures within cabinet 10.

Cabinet 10 also includes a second cable entry 50 allowing second cable 16 to enter cabinet 10. In the illustrated embodiment, second cable 16 is also an underground cable entering cabinet 10 from beneath base 17. Second cable 16 includes an outer conduit 52 with a plurality of inner microducts 54. Conduit 52 is clamped with a clamp 56 to a clamp panel 58. Microducts 54 are typically installed for later use when an optical fiber interconnection is desired. Cable installation devices are known which insert optical fibers into hollow ducts, such as through a blowing operation which uses pressurized air to install the optical fiber in the duct. Cabinet 10 allows for initial placement conduit 52 with microducts 54 where the optical fibers 60 are installed at a later date in microducts 54.

A plurality of trays or shelves 70 hold ends 62 of microducts 54 with a microduct holder 200. Shelves 70 also hold fiber splices for joining fibers 60 to further fibers connected to first cable 14, as will be described below, thereby completing the connection between first cable 14 and second cable 16.

Referring now to FIGS. 6-8 and 23, first cable 14 in the form of feeder subunit cables 80 enter splice drawer 100. Splice drawer 100 includes a chassis 102 and a moveable tray 104. Moveable tray 104 holds one or more splice trays 106. Splice trays 106 include splice chips 108 which hold the individual splices 110 between feeder subunit cables 80 and feeder pigtails 82.

Referring now to FIGS. 9, 10 and 23, feeder pigtails 82 are shown being connected to splitter input cables 84 in a connector drawer 120. Connector drawer 120 includes a chassis 122 and a moveable tray 124. Mounted on tray 124 is a plurality of terminations of 126. Terminations 126 include a connector 128 on the end of each feeder pigtail 82 and each splitter input cable 84 which are joined together in an adapter 130.

Splice drawer 100 and connector drawer are mounted to panel 36 at mounting strips 39 which receives fasteners. Further features of splice drawer 100 and connector drawer 120 are shown and described in greater detail in U.S. Pat. Nos. 6,438,310, 6,504,988, and 7,079,744, the disclosures of which are hereby incorporated by a reference.

Referring now to FIGS. 11-14, splitter input cables 84 are shown being split into splitter output cables 86 which are either stored in a fiber storage device 150 (FIG. 13) or terminated to other cables at connector panel 160 (FIG. 14). Each splitter module 170 includes an input port 172 and one or more output ports 174 in the illustrated embodiment. For example, each splitter module 170 can split a splitter input cable 84 into a plurality of splitter output cables 86, such as a 1×32 splitter. Splitter modules 170 are mounted in a chassis 176 which mounts to mounting strips 39 with fasteners. A cable manager 180 helps manage slack associated with splitter output cables 86.

When splitter output cables 86 are not yet needed for connection to downstream equipment, storage panel 150 is used to hold each splitter output cable 86. Preferably, each splitter output cable 86 includes a connector 128. Preferably, connector storage panel 150 can receive each connector 128, or a group of connectors, including a dust cap over an end of a ferrule associated with connector 128. Further features of exemplarily connector storage panels 150 and holders are shown and described in U.S. Pat. No. 7,218,827, the disclosure of which is hereby incorporated by reference.

When a downstream connection is desired, a splitter output cable 86 is removed from connector storage panel 150 and connected to a front of connector panel 160. Referring now to FIGS. 15 and 16, connector panel 160 includes a plurality of adapters 130 for joining two connectors 128. Once connected, splitter output cable 86 is optically linked to a distribution pigtail 88 which is led from connector panel 160 to one of shelves 70. Connector panel 160 in the illustrated embodiment has a chassis 163 mounted to mounting strips 39 with fasteners, and a pivoting panel 164 for holding the adapters 130. A cable manager 182 (FIG. 4) manages distribution pigtails 88 between connector panels 160 and shelves 70.

Referring now to FIGS. 17-22, distribution pigtails 88 are joined to fibers 60 through splice tray 190 on each shelf 70. Each shelf 70 includes a microduct holder 200 which holds an end 62 of one of the microducts 54. Specifically, microduct holder 200 includes a plurality of holes 202 which are sized to closely surround an exterior of each microduct 54. The circular periphery defined at each hole 202 engages an exterior of the microduct 54 to frictionally hold the microduct relative to shelf 70. In the illustrated embodiment, microduct holders 200 are shown positioned in a side plate 204 of each shelf 70. The holes 202 can be punched from sheet metal. If desired, an insert can be mounted to shelf 70, or to a vertical panel adjacent to shelf 70 so as to provide the circular holes 202 separate from shelf 70. Also, a variety of microducts 54 can be used. A differently sized microduct holder 200 is utilized for different microducts. For example, an outside diameter of the microducts can vary from 3 millimeters, to 5 millimeters, to 7 millimeters. To facilitate insertion, an end 62 of each microduct 54 is provided with a tapered shape (45 degree angle) so as to permit easier insertion in each hole 202. This can be cut off square as desired after insertion. In the case of a 5 millimeter duct, a hole having a diameter of 0.189 inches+/−0/0.002 inches will allow insertion of each duct without excessive effort or damage to the duct, and then retain each duct with sufficient retention force.

On a base 208 of each shelf 70 a tie device 210 can be provided for tying ends 62 of microducts 54 to each other or to each shelf 70. Base 208 of each shelf 70 further includes cable radius limiters 212 for managing the cables on each shelf 70. Shelf 70 further includes splice tray mounts 214 for holding splice trays 190 on shelves 70. Each splice tray 190 includes a splice chip 192 for holding a splice 194 used to join each distribution pigtail 88 to each fiber 60.

Each shelf 70 further includes a slot 220 for use in passing first cable 14 from base 17 to splice drawer 100 located adjacent a top 21 of cabinet 10. Shelves 70 further include an aperture 222 for allowing distribution pigtails 88 to pass to the appropriate shelf 70 for connection to the fibers 60 located on each shelf 70.

In this manner, microducts 54 can be installed to cabinet 10, and the blown fiber inserted later. It is anticipated that the blown fiber can be inserted from either end of microduct 54, either at end 62, or at the remote end disposed at the remote site.

Cabinet 10 manages the feeder cables 14 and the duct 54 of the distribution cable 16, so that a user can install blown fiber at a later date, and then make appropriate connection to the feeder cable, such as with a splice on shelf 70. The other functions provided by cabinet 10 also allow ease of use, such as the access provided by each of drawers 100, 120, splitters 170, connector panel 160, as well as the various cable managers. 

1. A method of managing cable in a telecommunications system comprising: providing an enclosure including an interior, the interior receiving a feeder cable and a conduit including microducts; routing the feeder cable to a splicing area including a plurality of horizontal shelves, each horizontal shelf including a cable splice tray and a microduct holder, wherein the microduct holder defines a plurality of holes for holding at least some of the microducts; routing the conduit adjacent to one of the horizontal shelves, wherein the microducts are held by the microduct holder; blowing a fiber through one of the microducts; and splicing the fiber blown through one of the microducts to the feeder cable.
 2. The method of claim 1, wherein the plurality of holes of each shelf includes a plurality of rows and columns of holes in a sheet metal plate.
 3. The method of claim 1, wherein each of the holes frictionally engages one of the microducts.
 4. The method of claim 3, wherein each hole defines a circular periphery that frictionally engages an exterior of the microduct. 